I use one of my own photographs on my business card. I make a "sheet" of them in photoshop and print them out on 8x10 paper and cut them out myself with a roll cutter.
Come out pretty cheap ($15 per 100) for a good quality card printed on honest to goodness photo paper and the folks to whom I give them really seem to like them. It is kinda like passing out samples.

I have heard good things about VistaPrint...and my first order from them is in en-route as we speak. They are having a 'sale' right now. I think 250 cards is $3.99 or something like that. You can even get free ones, if you don't mind their logo on the back.

Personally, I like simple cards. Nothing too fancy. If you are going to include an image, make it a simple one and what ever you do, make sure the text/info is clear and easy to read.

I actually used Microsoft Publisher to design my cards and got them printed at Kinko's. I imagine I do not have the most beautiful cards in the world but I do have one of my photographs on it and I think they are very nice. Kinko's will print them and cut them down to size for a very reasonable price. Of course right now I forget what I paid but it was not expensive at all.